under-reporting; under-declaration
Primarily used in tax contexts for reporting less income or deductions than actually applicable. Also used in other official declarations.
The tax office pointed out the under-reporting.
An additional tax for under-reporting may be imposed.
過大申告 means over-reporting, the opposite of 過少申告.
申告漏れ refers to an omission in reporting, which may be unintentional, while 過少申告 often implies a deliberate understatement.
penalty tax for understatement of income
Compound of 過少 (too little, insufficient) and 申告 (declaration, report).